With advances in long-distance, multiplex communication technologies using optical cables, many-to-many optical multistage selectors are under research and development.
Specifically, there are fiber drive type optical switches in which a magnetically clad fiber is directly driven by an electromagnetic to change the path of light, micro-mirror type optical switches in which the light reflection angle is changed by using an MEMS mirror to change the passage path of light, waveguide-type optical switches in which after dividing light into two rays with different phases, one of the rays is subjected to phase inversion by heat so as to interfere with the original light, thereby switching light ON-OFF, and optical multistage switches using an optical sheet bus or the like. Switching of communication signals has been performed by configuring a many-to-many optical multistage selector by these techniques.
However, such optical switches are expensive with a large housing size, making them unsuitable for incorporation into general consumer appliances.
In view of this, there has been proposed a system in which each function of a product is modularized to facilitate addition and exchange of the function on an optical sheet bus (see, for example, Japanese Unexamined Patent Application Publication No. 10-123350).
In optical sheet buses according to the related art, scatterers are placed in a dispersed manner across the entire light transmission layer so that incident signal light is transmitted while being diffused, thereby enabling transmission of a signal between a plurality of boards connected to the optical sheet bus.